|Lots of things can cause freezes. Improper ram settings is only one of them. |
Ram that works in another mboard , or any ram you buy or have lying around, may not work properly, or sometimes, not at all - even if it physically fits and is the right overall type (e.g. SDram, DDR, DDR2, etc.; PCxxxx, xxx mhz) for your mboard. In the worst cases of incompatibilty your mboard WILL NOT BOOT all the way with it installed, and the mboard may not even beep - the ram has to be compatible with the mboard's main chipset, or in the case of recent mboards, compatible with the memory controller built into the cpu.
See response 5 in this for some info about ram compatibilty, and some places where you can find out what will work in your mboard for sure:
Correction to that:
Once you know which module ID strings work in your mboard, you can get them from anywhere you like that has ram with those ID strings.
If you have brand name ram, it is usually easy to look up whether it's ID string is in a list of compatible modules found by using your mboard or brand name system model number.
If the ram is generic, that may be difficult or impossible.
"Go to bios and make sure settings are correct don't accept defaults."
Some module makers don't adhere to the Jadec standards that most bioses use. In that case, the default settings the bioses uses may be incorrect for your ram modules. Go by the voltage and timing ratings for the module(s) you are using - if the default settings don't match that, set the bios settings for those as close as you can get to the modules ratings, or lower/slower.
If you have a mix of modules, it is recommended that you do NOT install ones that have different voltages specified for them - they should use the same voltage - standard or non standard. The timings must be set to the slowest settings or slower of all of the modules installed if they are different, or slower (slower = higher numbers). You won't notice the slower settings make a difference as far as performance goes.
Don't exceed the max range of voltages for the module - you may need to look that up on the manufacturer's web site.
Some also-ran module makers other than the major brands such as Kingston, Crucial, Corsair, Mushkin, etc. rate their modules when they are installed by thenselves in a mboard, but when you install more than one, they won't work properly unless you up the ram voltage .1 or .2 or set the timings for they are a bit slower. Major brand names usually actually test the ram modules in the mboard or system models they list with all the ram slots occupied, and the ratings of the ram are for when all the slots are occupied, and the stated ratings work fine. They are a lot more likely to conform to Jedec standards, and the default settings the bioses uses are more likely to be fine.
A common thing that can happen with ram, even ram that worked fine previously, is the ram has, or has developed, a poor connection in it's slot(s).
This usually happens a long time after the ram was installed, but it can happen with new ram, or after moving the computer case from one place to another, and I've had even new modules that needed to have their contacts cleaned.
See response 2 in this - try cleaning the contacts on the ram modules, and making sure the modules are properly seated:
If you do a ram test, do that AFTER having tried cleaning the contacts and making sure the ram is seated properly - otherwise any errors found may be FALSE.
If the ram is incompatible with the chipset, or on more recent computers, incompatible with the memory controller built into the cpu, it will likely FAIL a ram test - that is NOT a true indication of the ram being faulty - there is probably nothing wrong with it, and it will pass the test if installed in a mboard it is compatible with.
If you want to try a memory diagnostic utility that takes a lot less time to run a full pass than memtest86 does, this one is pretty good - Microsoft's
Windows Memory Diagnostic:
It can be toggled (press T) to do a standard or a more comprehensive set of tests - use the default 6 test one first - if it passes one pass of that, use the latter one. A few of the tests in the latter set are intentionally slower.
If you don't have a floppy drive, see the Quick Start Information at that Microsoft link for how to make a bootable CD of the Windows Memory Diagnostic (you need Windiag.iso - you don't necessarily need to use the program they mention to add it to the CD).
Your power supply must have at least the minumum capacity required to support a system with the graphics card you are using installed, or the max graphics card you might install in the future.
(Onboard video - video built into the mboard - IS NOT A CARD!)
You can go to the video card maker's web site and look up the specs for the model - often under system requirements - the minimum PS wattage, and, more important, the minimum amperage the PS must supply at 12v is stated. If you don't find that, any card with the same video chipset including any letters after the model number has very similar minimum PS requirements. Some power supplies have two or more +12v ratings - in that case, add those ratings to determine the total +12v current capacity.
ATI Radeon™ HD 4890 System Requirements
PCI Express® based PC is required with one X16 lane graphics slot available on the motherboard
500 Watt or greater power supply with two 75W 6-pin PCI Express® power connectors recommended (600 Watt and four 6-pin connectors for ATI CrossFireX™ technology in dual mode)
Certified power supplies are recommended. Refer to http://ati.amd.com/certifiedPSU for a list of Certified products
"PSU: Corsair TX 650W"
The max wattage is almost always an intermittant rating.
It's recomended that you do NOT load your PS to more than 80% of that for constant loads, such as while you're playing recent games for hours on end.
1 divided by .8 = 1.25
1.25 X 500 min for the 4980 = 625 watts
So your PS capacity is okay, presumably.